1. Field of the Invention
This invention relates to traffic monitoring systems, and more particularly, to such systems that provide instantaneous, continuous, and specific information on traffic congestion.
2. Description of the Related Art
Many municipalities use video cameras perched on top of tall poles located at different locations along roadways to monitor traffic congestion. The video cameras are operated by individuals in a central viewing office who watch a bank of monitors showing images of the traffic from the video cameras. By watching these images, trained individuals are able to analyze the traffic congestion and provide some quantitative measurement, (i.e. stopped, slow, below or at speed limit; and light, moderate, heavy, grid-locked, respectively). Local television and radio stations are able to broadcast this information to drivers who turn on their televisions and radios for the latest traffic update. This method of monitoring and reporting traffic congestion is commonly referred to as the view-and-relay method.
One problem with the view-and-relay method is that information is not instantaneously updated and immediately available to drivers. With dozens of video cameras located around a region, it often takes several minutes before an accident or a slow down on a roadway is recognized and reported to the public. When a report is finally given, the precise location or cause of the traffic congestion and the lanes of traffic affected can be difficult to determine. The quantitative terms used to describe the resulting traffic congestion may be too vague to be useful.
Another problem with the view-and-relay method is that it does not provide estimated travel time between points on a route. Knowing such information, estimated times of arrival (ETA) from a starting location to a desired destination following a preferred route or following alternative routes could be provided taking into consideration current or future traffic conditions along on roadways used in the routes.
Another problem with the view-and-relay method is that it does not provide comparative roadway traffic congestion information that would allow drivers to choose alternative, less congested roadways. In a large metropolitan area, alternative roadways are usually available for reaching a desired destination. Knowing the current and anticipated traffic conditions on the preferred roadway and on alternate roadways would allow drivers to adjust their plans regarding which routes to reduce their travel time and to more evenly distributed traffic flow over all the roadways in the region.
Another problem with the view-and-relay method is that it does not provide information on the flow of traffic in the individual lanes. It is well known that the flow of traffic in individual lanes in a multiple lane roadway can vary greatly. While accidents and merging traffic is often the cause of the variation, in some instances drivers with different driving styles cause the variations. Knowing which lane is flowing faster would be desirable for many drivers.
A further problem with the view-and-relay method is that it does not provide predictive or anticipated traffic congestion information. For example, how is traffic congestion on a freeway impacted when a lane closes for construction at 10:00 P.M.? Or, is traffic congestion on different roadways in the region impacted when a large sporting event ends? To answer these questions, both current and anticipated traffic congestion information on selected roadways must be known. Unfortunately, the view-and-relay method does not provide this information.